My take is that - as long as the "dupe" poster posts a link to the original, the exercise serves a valid purpose.
1) It gives those of us who occasionally check page 1 of active topics a chance to see someting memorable or funny that may otherwise have been buried.
2) Then, we can make whatever comments on the original thread and bump it back to the top, breathing new life in to it as needed.
A separate area of the board with links to videos, pics, news stories, etc. would be no different than actually surfing those places on the net where this stuff is the sole reason people go there - and many of us still would never go there to see them. As it is now, there are news links on the main hom page of this site, but most of us never see them until someone actually starts a thread about them.
My pet peeve (one of many, I'll admit) is simply the "dupe" posters who don't bother posting a link.